CVE-2026-89459 (GCVE-0-2026-89459)
Vulnerability from cvelistv5
Published
2026-09-11 19:43
Modified
2026-10-19 08:47
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
s390/percpu: Fix MVIY_PERCPU() with older binutils
Commit a737737cdb9c ("s390/percpu: Infrastructure for more efficient
this_cpu operations") introduced MVIY_PERCPU(), which stringifies
arguments that are already C string literals. This generates an
assembler macro invocation with whitespace-separated quoted arguments:
GEN_MVIY "459712" "%r3"
GNU as versions prior to binutils 2.39 drop the separating whitespace
between quoted macro arguments during input scrubbing. They
consequently parse the invocation as a single argument and emit
repeated warnings:
Warning: missing closing `"'
The .ifc in GEN_MVIY never matches and GNU as exits successfully
without emitting the mviy instruction. As a result, the interrupted
per-CPU sequence is not marked in lowcore and the exception return
path cannot repair the per-CPU address register after migration.
All MVIY_PERCPU() callers pass C string literals. Use them directly
and separate the assembler macro arguments with an explicit comma. The
resulting invocation is:
GEN_MVIY 459712, %r3
This form is unambiguous for GNU as and LLVM's integrated assembler.
This behavior was fixed in GNU as from binutils 2.39, but Linux
supports binutils 2.30.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/s390/include/asm/percpu.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "91770b08a120967077ae78600612f18bc5ee3caf",
"status": "affected",
"version": "a737737cdb9c94e40a9926cdc2320f874c05d709",
"versionType": "git"
},
{
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"status": "affected",
"version": "a737737cdb9c94e40a9926cdc2320f874c05d709",
"versionType": "git"
}
]
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{
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"product": "Linux",
"programFiles": [
"arch/s390/include/asm/percpu.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.2"
},
{
"lessThan": "7.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
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],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.4",
"versionStartIncluding": "7.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "7.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/percpu: Fix MVIY_PERCPU() with older binutils\n\nCommit a737737cdb9c (\"s390/percpu: Infrastructure for more efficient\nthis_cpu operations\") introduced MVIY_PERCPU(), which stringifies\narguments that are already C string literals. This generates an\nassembler macro invocation with whitespace-separated quoted arguments:\n\n GEN_MVIY \"459712\" \"%r3\"\n\nGNU as versions prior to binutils 2.39 drop the separating whitespace\nbetween quoted macro arguments during input scrubbing. They\nconsequently parse the invocation as a single argument and emit\nrepeated warnings:\n\n Warning: missing closing `\"\u0027\n\nThe .ifc in GEN_MVIY never matches and GNU as exits successfully\nwithout emitting the mviy instruction. As a result, the interrupted\nper-CPU sequence is not marked in lowcore and the exception return\npath cannot repair the per-CPU address register after migration.\n\nAll MVIY_PERCPU() callers pass C string literals. Use them directly\nand separate the assembler macro arguments with an explicit comma. The\nresulting invocation is:\n\n GEN_MVIY 459712, %r3\n\nThis form is unambiguous for GNU as and LLVM\u0027s integrated assembler.\nThis behavior was fixed in GNU as from binutils 2.39, but Linux\nsupports binutils 2.30."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The omitted mviy start marker is in s390 this_cpu_read/write/add sequences reached from local syscalls (mm/swap, memcg, vmalloc) and user-namespace nftables; this is an arch per-CPU primitive, not a packet parser, ksmbd/nfsd handler, or USB path.\nAC:H - The op is wrong only if an interrupt or preemption and a CPU migration both occur after AG adds the old CPU offset and before the atomic instruction; that one-instruction window is not attacker-timed, even with affinity bouncing on default PREEMPT_LAZY s390.\nPR:L - Any unprivileged local user can drive this_cpu_* via ordinary syscalls, and nft_ct\u0027s this_cpu_read(nft_ct_pcpu_template) is reachable with CAP_NET_ADMIN in a user namespace; init-namespace root is not required.\nUI:N - The attacker triggers the unmarked this_cpu sequences from their own process (syscalls or locally generated packets); no victim mount, file open, or other interaction is required.\nS:U - Stale per-CPU pointers are used inside the same host kernel after migration; this is not a KVM/Xen guest-to-host escape or IOMMU/DMA boundary bypass.\nC:H - After migration, this_cpu_read uses another CPU\u0027s pointer-typed slots (percpu_swap_cluster.si, nft_ct_pcpu_template, page-pool/socket pointers) without that CPU\u0027s locking, which can disclose kernel objects and is memory corruption leverageable for info disclosure.\nI:H - The matching this_cpu_write/add then mutates the previous CPU\u0027s per-CPU state (swap cluster cache, conntrack templates, other CPU-local structures that assume exclusive access), which is kernel memory corruption exploitable toward control-flow hijack.\nA:H - A stale per-CPU pointer after migration can oops or panic (NULL vmalloc ne_fit_preload_node, inconsistent swap_info, conntrack refcount UAF), which is a full kernel availability loss on SMP s390."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T08:47:08.639Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/91770b08a120967077ae78600612f18bc5ee3caf"
},
{
"url": "https://git.kernel.org/stable/c/101782f8945a125044347312d74d488c05741c4a"
}
],
"title": "s390/percpu: Fix MVIY_PERCPU() with older binutils",
"x_generator": {
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}
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-89459",
"datePublished": "2026-09-11T19:43:22.007Z",
"dateReserved": "2026-09-11T19:38:34.707Z",
"dateUpdated": "2026-10-19T08:47:08.639Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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